<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <style>
        ul.table{
            border:1px #ccc solid;
            margin-top:100px;
            list-style: none;
            padding: 0;
            margin-top: 0;
            margin-bottom: 0;
        }
        ul.table li{
            border-bottom: 1px #ccc solid;
            list-style: none;
            /* margin-bottom: -1px; */
        }
    </style>
    <title>去除列表最后一个li元素的border-bottom</title>
</head>
<body>
        <ul class="table"> 
            <li>I am li</li>
            <li>I am li</li>
            <li>I am li</li>
            <li>I am li</li>
            <li style="margin-bottom: -1px;">I am li</li>
        </ul>
</body>
</html>